How Low-E Window Films Can Help You Save Energy and Reduce Costs

Murrye Bernard is an independent writer based in New York City, specializing in sustainable home renovation methods in architecture.

As the sun shines intensely on your home, both heat and ultraviolet (UV) rays can penetrate through the windows. These UV rays and the heat from the sun can increase the temperature inside your house and harm various possessions. One effective solution to reduce heat and protect your belongings is to invest in windows that feature a low-E coating. Alternatively, you can also apply low-E film to your existing windows.

Low-E film differs from window insulation film, which is used to minimize drafts. It serves as a more affordable option compared to purchasing windows with factory-installed low-E coatings. In the United States, Low-E rolls are not available for do-it-yourself projects and must be installed by a professional window company.

Keep reading to learn about low-E film, its effects, and the advantages and disadvantages it offers.

Film Accessible for Do-It-Yourself Enthusiasts

While Low-E film might not be accessible for do-it-yourself enthusiasts in the United States, there are other options available online. You can explore heat-rejecting and UV-blocking films, as well as metal alloy films that can be easily applied and removed. Additionally, you might want to look into vinyl window tint films that use static cling for application.

What is Low-E Coating?

Low-E film, often referred to as solar or climate control window film, is a slim layer of plastic or metal that is applied to the interior of windows to enhance comfort, privacy, safety, and security. This film is effective in energy conservation, as it can block as much as 99 percent of ultraviolet rays that would typically enter a home. Available in rolls, Low-E film is primarily sold to professional window installation services. The term “Low-E” stands for “low-emissivity,” and these films typically incorporate metal or metal oxide to mitigate the effects of UV radiation.

Producers frequently claim that low-emissivity films can reflect approximately 70-80% of solar heat during the summer months and retain more than 50% of indoor heat during the winter season.

If you’re not ready to upgrade to new, energy-efficient windows equipped with factory-installed low-E coatings, think about applying low-E film to enhance energy efficiency and achieve long-term savings on energy expenses.

What is the price of Low-E film?

The expense of applying low-E film to windows ranges from $4 to $19 per square foot, covering both materials and installation. Nonetheless, this service is exclusively offered by commercial installers in the United States.

Installing low-E film is considerably more cost-effective compared to the installation of factory-produced low-E glass windows, which range from $40 to $55 per square foot. Windows that come with low-E coatings generally have a price increase of around 10% to 15% compared to standard windows, yet they can decrease energy loss by 30% to 50%.

According to estimates, low-E products have contributed to a savings of $43 billion in yearly utility expenses for households across the United States.

Applying Low-E Window Film

In various nations, such as the United Kingdom, the installation of low-E film can be tackled as a DIY task. Conversely, in the United States, these films are exclusively accessible through professional window installation services. Generally, these films are straightforward to apply and can be removed without much hassle. Nonetheless, achieving a bubble-free application can be time-consuming, and ensuring the edges and corners adhere properly can be challenging. If you’ve ever placed a screen protector on a smartphone or tablet, the installation process is akin to that, albeit on a much larger surface.

Factors to Take into Account Prior to Applying Low-E Film

More Efficient in Specific Circumstances

Take into account the climate of your area and the direction your windows face. Examine the solar heat gain coefficient (SHGC) and the visible transmittance (VT) rating of your windows. SHGC indicates the level of solar radiation that penetrates the window, while VT assesses the amount of visible light that can pass through. Depending on your location and the amount of sunlight your windows receive, applying low-E film can significantly influence your energy costs.

Safeguards Home and Possessions

In addition to its heat-reflective properties, low-E film minimizes glare indoors and enhances privacy while maintaining visibility. In certain instances, this film can obstruct as much as 99% of ultraviolet rays. UV radiation can harm or discolor furniture, fabrics, and artwork.

Low-E film can help maintain the resale value of your home by safeguarding the flooring, which tends to be more costly or challenging to repair or replace.

Could potentially invalidate the window warranty.

One possible drawback of applying low-E film is that it may invalidate the warranty on specific windows, especially those that are double-paned. The low-E film can lead to differing expansion rates between the interior and exterior panes of glass, which might result in cracking.

Advantages and Disadvantages of Low-E Coatings

• Shields against ultraviolet radiation.
• Lowers solar heat absorption, maintaining a cooler indoor environment.
• Safeguards the surfaces within the home.
• Simple for installers to implement.
• Temporary connection
• Reduces energy expenses.
• More affordable than low-E glass.

• Projects a hue indoors or provides a reflective, mirror-like appearance on the outside.
• Installation must be carried out by professionals within the United States.
• Indoor plants get reduced sunlight.
• Could potentially invalidate the window warranty.
• Certain ones might prove challenging to eliminate.
• Provides assistance solely with sunlight exposure, not with drafts.

Low-E Coating vs. Window Insulation Film

If your house feels chilly or your windows have drafts, low-E film isn’t the right solution for installation. This film only applies to the glass area of your windows, leaving the frames untouched, which means it won’t help with drafts. For better insulation and to seal your home, consider using window insulation film, caulking, or weather stripping.

Window insulation film is affixed to the window frame using double-sided adhesive tape, rather than being applied directly to the glass, which creates an insulating gap between the film and the glass surface. The heat from a hairdryer is used to shrink the film, enhancing its resistance to air infiltration.

Window insulation film is nearly see-through, ensuring that your view remains unobstructed. Over time, the film may develop wrinkles or ripples, but these can usually be smoothed out by reapplying the film or using a hairdryer. Since most insulation films are transparent, they allow sunlight and UV rays to pass through without obstruction.